Reduction reactions during fatty acid synthesis utilize NADPH.
Fatty acids are synthesized by the repetition of the following reactions: condensation, reduction, dehydration, and reduction.
Synthesis takes place in the cytosol and the enzymes included synthesis in this process are joined in a protein fatty acid synthase. During the process, the growing fatty acid chain is elongated by the sequential addition of two-carbon units derived from acetyl CoA. The reductant is NADPH.